The invention relates to methods and systems for registering and sorting out packages having not properly filled deep-drawn compartments, in a packaging installation. Typically, these packages comprise a base foil in which the compartments to be filled are formed by deep-drawing. The compartments are then filled, and a cover foil is applied to seal them, forming a strip of such packages which is transported through the packaging installation.
Usually, the base foil is pulled off a supply roll and transported via guide rollers to a deep-drawing station, at which compartments are formed by deep-drawing. The deep-drawn base foil is transported through a filling station where the individual compartments are filled. The base foil is then transported through a sealing station, where a cover foil is applied and sealed to the base foil along predetermined seal lines. The strip of packages is then transported through a stamping or cutting station, where the strip is severed transversely (and also longitudinally in certain cases) to form the individual packages. Typically, each package is comprised of an orderly group of compartments arranged in rows extending both parallel to and transverse to the transport direction. After the individual packages are severed from the strip, they are transported through a sorting station, where not properly filled packages are sorted out. The examination of compartments arranged in transverse and longitudinal rows, and the automatic discarding of the packages into which the orderly groups of compartments are cut, present problems to which a reliable general solution has not hitherto been found.
It is known to provide a testing station intermediate the filling station and the sealing station. Mechanical devices located above the open compartments of the base foil, such as sensing pins, levers or lever-mounted rollers, move into the individual compartments until they contact the goods therein. This provides a direct indication of the extent to which the compartments are properly filled. The sensing elements must be organized in correspondence to the organization of the compartments in each successive group of compartments to be tested (e.g., 3 by 4). Thus, in general, each such sensing arrangement is limited to use for compartments exhibiting a predetermined organization and set of dimensions. Each time compartments of different organization or dimensions are to be tested, the set of sensing elements must be replaced by another. Furthermore, because these sensing elements must physically contact the goods in the individual compartments, the testing operation must be performed before the cover foil is applied to the deep-drawn base foil.
It is known to test without physically contacting the goods in the compartments. A light source is arranged at one side of the transported strip of uncut packages, and a light detector at the other side. The intensity of the light transmitted through the individual compartments and incident upon the light detector provides an indication of whether the compartments are properly filled. If the testing operation is performed prior to application of the cover foil, then at least the base foil must be transparent; if performed after the cover foil is applied, then both the base foil and the cover foil must be transparent.
It is also known to arrange the light detector to receive light reflected from the individual compartments. The amount of light reflected from a not properly filled compartment is presupposed to differ from that reflected from a properly filled compartment. The utility of this technique is limited to situations where a reliable distinction exists between the reflection of light from properly and not properly filled compartments, for example where the compartments contain tablets.
Another known technique involves weighing the transported strip of packages at a weighing station upstream or downstream of the sealing station. This technique presupposes that the detected weight of properly and not properly filled packages can be reliably distinguished, and that variations in other parameters, such as the weight of sections of foil of somewhat varying thickness, will not lead to the generation of discard signals.